M. E. MacGregor 
183 
they are not far from being parallel also with the median sagittal plane 
of the larva. The slits themselves are comparatively broad, with the 
bars arranged at the “ extreme edge ” position. Of these there are a 
fairly large number, but their form resembles that found in Lucilia 
caesar, rather than that of Gynomyia cadaverina. 
Another strikingly different feature, and one, as has been already 
said, that has only been found to be shared by Chrysomyia (sp. incert.), 
occurs in the “ ring.” In the stigmata of Sarco])haga sarraceniae this 
“ ring ” is especially distinct and delicate, but at the point where in 
the other specimens the “ button ” is situated, the “ ring ” is broken 
and a gap occurs. Thus in the stigmal plate the “ button ” is absent 
altogether, though the broken ends of the “ ring ” are somewhat 
Text-fig. 2. Posterior stigmata of (a) Sarcophaga sarraceniae and (b) Chrysomyia (?). 
Diagram of one plate of each to show different arrangement of slits. 
thickened and rounded. Taking into account first the almost parallel 
arrangement of the slits, and then this latter feature, the larvae of this 
fly are very easily recognised, and there is no need to consider also the 
finer structure in order to differentiate it satisfactorily from all the 
others except Chrysomyia (?). From this genus it can however be 
distinguished by the fact that in Chrysomyia (sp. incert.), though the 
general arrangements of the slits and the “ ring ” are similar to those 
of Sarcophaga sarraceniae, in the former the slits, while parallel with 
one another, are diagonally arranged, and cannot in any way be con¬ 
sidered as parallel with the median sagittal plane of the body. 
